Gluing foam seams with contact cement

This page has safety advice that hasn't yet been checked by our safety reviewer. Treat it as general guidance, and follow your game's, venue's or product's own safety rules first.

A guide to bonding EVA foam edges cleanly with contact cement, suited to beginner and intermediate cosplay armour builders.

Contact cement is one of the most common ways to join pieces of EVA foam because it creates a flexible, durable bond that moves with the costume rather than cracking under wear. Unlike white glue or hot glue, contact cement is applied to both surfaces, allowed to become tacky, and then the two sides are pressed together for an almost instant join. This means you get very little chance to reposition, so taking a moment to test-fit your pieces before gluing pays off. To prepare your foam edges, make sure they are clean, dry, and free of dust or release agents. Some cosplayers lightly sand cut edges to remove any shiny skin left by a heat knife or blade, since a slightly roughened surface gives the cement more to grip. Apply a thin, even coat of contact cement to both mating surfaces using a brush, a foam applicator, or the built-in brush in the tin, depending on what your product includes. Watch the coating change from glossy to matte, which is the sign it is ready. Press the two surfaces together firmly and hold for a short time. Check your product's instructions for the recommended open time and curing period, as these vary between brands and between hot and cold environments. For curved seams, some makers score or bevel the foam edges at an angle before gluing so the pieces close into a smooth arc rather than a flat butt join. Once the cement has fully cured, you can pass a heat gun gently over the outside of the joint to help the seam blend in, then seal and paint as normal. Wet contact cement and its fumes are flammable, so never bring a heat gun near a seam until it has cured. Safety is important with contact cement. Most solvent-based formulas release fumes that can build up quickly in a closed space, so always work outdoors or in a room with strong cross-ventilation, and wear a respirator fitted with organic-vapour cartridges rather than a simple dust mask. Water-based contact cements give off fewer fumes, but you should still ventilate the room. Nitrile gloves protect your skin from prolonged contact. Keep the tin sealed when you are not actively applying, store it away from heat sources and open flames, and keep it out of reach of children. If you are under eighteen, work with an adult present.